<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>houzi</title>

    <script type="text/javascript">
        function taozi() {

            var i = 1;
            for (var day = 9; day >= 1; day--) {
                i = 2 * (i + 1);
                console.log("第" + day + "天" + "有" + i + "个");

            }


        }
        taozi();
    </script>
</head>

<body>

</body>

</html>